<template>
  <div>
    <router-link tag="div" to="/" class="header-abs"
    v-show="showAbs"
    >
      <div class="iconfont header-abs-back">
        &#xe624;
      </div>
    </router-link>
    <div class="header-fixed"
    v-show="!showAbs"
    :style="opacityStyle"
    >
      <router-link to="/" tag="div">
        <div class="iconfont header-fixed-back">
          &#xe624;
        </div>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
  export default {
    name: 'DetailHeader',
    data(){
      return{
        showAbs:true,
        opacityStyle:{
          opacity:0
        }
      }
    },
    methods:{
      handleScroll(){
        const top = document.documentElement.scrollTop || document.body.scrollTop ||window.pageYOffset
        if(top>60){
          let opacity = top / 140
          opacity = opacity > 1 ? 1:opacity
          this.opacityStyle ={
            opacity:opacity
          }
          this.showAbs = false
        }else{
          this.showAbs = true
        }
      }
    }
    ,
    mounted(){
      window.addEventListener('scroll',this.handleScroll)
    },
    destroyed() {
      window.removeEventListener('scroll',this.handleScroll)
    }
  }
</script>
<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
  .header-abs{
    position :absolute
    left :.2rem
    top :.2rem
    width :.8rem
    height :.8rem
    line-height :.8rem
    border-radius :.4rem
    text-align :center
    background :rgba(0,0,0,.8)
  }
  .header-abs-back{
    color:#FFFFFF
    font-size :.4rem
  }
  .header-fixed{
    z-index :2
    position :fixed;
    top :0
    left :0
    right :0
    height :.86rem;
    line-height :.86rem;
    text-align :center;
    color :#FFFFFF;
    background :$bgColor;
    font-size :.4rem;
  }
  .header-fixed-back{
    position :absolute;
    top :0;
    left :0;
    width :.64rem;
    text-align :center;
    font-size :.4rem;
    color :#FFFFFF;
  }
</style>
